LFEBS12UB Freescale Semiconductor, LFEBS12UB Datasheet - Page 847

• Manufacturer Part Number: LFEBS12UB
• Description: KIT STUDENT LEARNING S12 DG128
• Manufacturer: Freescale Semiconductor

Specifications of LFEBS12UB

• Architecture: 8/16-bit
• Code Gen Tools Included: Code Warrior
• Silicon Manufacturer: Freescale
• Core Architecture: S12
• Core Sub-architecture: S12
• Silicon Core Number: MC9S12
• Silicon Family Name: S12D
• Kit Contents: HCS12 DG128 Learning Kit
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

24.3.2.2
The FSEC register holds all bits associated with the security of the MCU and Flash module.
All bits in the FSEC register are readable but not writable.
During the reset sequence, the FSEC register is loaded with the contents of the Flash security byte in the
Flash configuration field at global address 0x7F_FF0F located in P-Flash memory (see
indicated by reset condition F in
phrase containing the Flash security byte during the reset sequence, all bits in the FSEC register will be
set to leave the Flash module in a secured state with backdoor key access disabled.
Freescale Semiconductor
KEYEN[1:0]
RNV[5:2}
SEC[1:0]
Offset Module Base + 0x0001
Reset
2. FDIV shown generates an FCLK frequency of 1.05 MHz
Field
7–6
5–2
1–0
W
R
Backdoor Key Security Enable Bits — The KEYEN[1:0] bits define the enabling of backdoor key access to the
Flash module as shown in
Reserved Nonvolatile Bits — The RNV bits should remain in the erased state for future enhancements.
Flash Security Bits — The SEC[1:0] bits define the security state of the MCU as shown in
Flash module is unsecured using backdoor key access, the SEC bits are forced to 10.
Flash Security Register (FSEC)
F
7
KEYEN[1:0]
= Unimplemented or Reserved
F
6
1. Preferred KEYEN state to disable backdoor key access.
KEYEN[1:0]
Figure 24-6. Flash Security Register (FSEC)
MC9S12XE-Family Reference Manual , Rev. 1.23
00
01
10
11
Figure
Table 24-10. FSEC Field Descriptions
Table
Table 24-11. Flash KEYEN States
F
5
24-11.
24-6. If a double bit fault is detected while reading the P-Flash
Status of Backdoor Key Access
F
4
RNV[5:2]
Description
DISABLED
DISABLED
DISABLED
ENABLED
Chapter 24 128 KByte Flash Module (S12XFTM128K2V1)
F
3
(1)
F
2
F
1
Table
Table
SEC[1:0]
24-12. If the
24-3) as
F
0
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